Hiroshi Nakano (中野 浩司 Nakano Hiroshi), commonly known as Hiro, is Shuichi Shindou's childhood best friend and band mate. Hiro can read Shuichi like a book and knows what's going on even before Shuichi does. Hiro is also the guitarist in Bad Luck and, with Shuichi, has dreams to surpass Nittle Grasper. But like every other character in Gravitation, Hiro is a lot more than a pretty face.

Hiro is really good at math and just basic information all together which was shown in episode 4 when he was able to answer every question they gave him. He is more of a calm guy and he doesn't get over excited like Shuichi. and has a lot of information and just being wise for his age. He has a crush on Ayaka Usami (this stated in many episodes) and they talk over the phone a lot; Hiro once stated that they chatted for 10 hours straight.